Iliamna volcano is a large stratovolcano on the western side of the Cook Inlet, in Lake Clark National Park 220 km SW of Anchorage or 100 km NW of Homer.
There are several uncertain reports about activity in the past 250 years, but the only confirmed known historical eruptions were small to moderate explosive eruptions in 1876, 1867, and between 778 and 1879. A larger eruption with pyroclastic flows was dated by radiocarbon method and occurred between 300 and 140 years ago, but was not observed. Most of the sparse eruption reports from Iliamna are probably referring to strong activity of fumaroles located east and SE of the summit.
stratovolcano 3053 m / 10,016 ft
Cook Inlet (SW Alaska), 60.03°N / -153.09°W Iliamna volcano eruptions:
1953(?), 1952(?), 1933(?), 1876, 1867, 1843(?), 1793(?), 1778-79, 1768(?)
radiocarbon-dated: 1650 ?, 450 BC ?, 2050 BC ?, 5050 BC ? Typical eruption style: explosive
Iliamna webcams / live data Last earthquakes nearby
Please log in to post messages or reply.
Posted By: tompfeiffer [178.128.210.158] on Mar 09, 2012 09:25AM
Color codes & alert levels
We have placed the volcano at status level "yellow" (2 on a scale of 0-5, unrest). Our scale has no official meaning and is different from the USGS scale of color codes raning from 1-4 ("green"-"yellow"-"orange"-"red").
Seismicity has risen again at the volcano recently, earthquake-report mentioned. Events as large as M1.4 occurred along a (ring?) fracture located south of the volcano’s summit.
Current seismic signal from Iliamna (INE station, AVO)
A swarm of earthquakes has started yesterday near Iliamna volcano. This morning, a 3.7 quake occurred about 30 km to the east, the strongest event in this new pulse of seismic activity so far. ...more
The volcano had just been set back to status level "normal" by AVO almost a month ago, after the seismic unrest in 2012 had gradually declined over the past month. So far, AVO has not changed the alert status again. [less]
Alert level has been put back to "green", after a gradual decline in seismic activity has been observed since March 2012, even though some earthquakes are still being registered under the volcano.
Seismicity remains very slightly above background. Satellite images of the volcano over the past 24 hours have been obscured by clouds. AVO has received no reports of unusual activity at the volcano. (AVO)
No unusual activity has been observed or reported at Iliamna Volcano over the past week. ...more
The current level of activity at Iliamna does not indicate an imminent or certain eruption. Seismic activity appears to be declining gradually. A similar seismic swarm occurred at Iliamna Volcano in 1996-1997 and was not followed by eruptive activity. Prior to an eruption, AVO would expect to see a significant increase in earthquake activity beneath the volcano. [less]
Seismicity at Iliamna remained above background levels, although just slightly, during 25-27 March. When not obscured by clouds, satellite and web camera views showed nothing unusual.
Seismicity at Iliamna volcano continues to be above background levels and fumarolic activity and steaming has increased as well. ...more
Satellite images acquired during 9-16 March showed a plume drifting 56 km downwind that was likely water vapor. The report noted that long-lived fumaroles at the summit of Iliamna frequently produced visible plumes, but the current plume appeared to be more robust than usual. Scientists aboard an overflight on 17 March observed vigorous and plentiful fumaroles at the summit, consistent with the elevated gas emissions. Gas measurements indicated that the volcano was emitting elevated levels of sulfur dioxide and carbon dioxide. [less]
Today, AVO has raised the Aviation Color Code to YELLOW and Alert Level to ADVISORY at Iliamna Volcano following a sustained increase in seismic activity over the past 3 months. ...more
Current activity is characterized by numerous earthquakes that have varied in their number and magnitude over the past week. This sustained seismic activity does not mean that an eruption is imminent or certain. A similar seismic swarm was detected in 1996/1997 that was likely related to an intrusion of magma at depth did not culminate in an eruption. (Alaska Volcano Observatory) [less]
Seismic activity recorded at Iliamna volcano on 9 Mar 2012 (AVO)
Since the middle of January 2012, seismic activity at Iliamna volcano has increased with more than usual numbers of earthquakes greater than magnitude 2. ...more
It is common to have earthquake swarms in the vicinity of Iliamna, which are usually caused by magmatic intrusion at depth. The ongoing activity is being closely monitored by AVO seismologists. AVO for now has not raised the alert status, which officially remains at "green". Similar swarms have last occurred in 1996-97, and there was no eruption then. [less]
